Spark-plug



H. M. GRIMES.

SPARK PLUG.

APPLICATION FILED APR. 29. I918- 1,359,591. Patenmd Nov. 23,1920.

UNITED STATES ra rsu'r OFFICE.

HARRY M. GRIMES, OF KOKOMO, INDIANA.

Application fil ed April as.

'l'aaltw/wmifJung concern? v Be it known that I, .Hannr M. G ngstas,

a citizen of the United Sta'tcsresidlng at Kokomo, in the county of Howard and Statc'of Ixulianznhave inventedcertainnew and useful Improvements in spark-'llugs, of which the following is a specification, "This invention relates to an improved spark plug and has as its primary object to provide a device of this character cmploying a hollowshell providing a firing chamber adapted to communicate with the living chamber of an engine cylinder to wlnch the plug ls connectedv so that upon tlwpassage of an electric current throu 'h the plug. fucl mixture contained within tie firing chamber of thoshelll wi'll be ignited and expelled therefrom as a jet of.flame into the tiring chaniher of thc cylinder for 'thus effectually igniting the fuel charge.

' 'lhc invention has as a further object to provide a spark plug wherein a spark will he created )i'ithin the firiiw chainhcr of the shell sothat"ignii'ion will initially occur within the mass of fuel mixture in the shell for thus driving the ignited mixture from thefshcll as a jet of flame.

A; still further object of the invention is to prd'vide a construction wherein the'sparkin'g terminals of the plug wjllbe housed within the shell and thus protected from the cooling influences ofinflowing fuel mix- .turn into the-living chamber of the engine cylinder, and wherein a portion of the incoming mixture enterihgthe cylinder will be trapped within'the shell to lie heated by the wall thereof so that such trap )ed fuel mixture will readily ignite within the shell.

The invention has as.u still further ob.- ject to provide a spark plug having the main electrode thi-reol so mounted that compression occurring within the engine cylinder will act to more firmly 'seat the said electrode to provide a sealed joint between the such electrode and its supporting member so that leakage through the plug will beprcvented i And the invention has as a still further object to provide a plug which will he particularly.characterized by simplicity of construction to 'thcend that the plug may he readily produced,

Other and incidental objects will appear as the description proceeds. In the draw ings wherein I have illustrated the pre- Specification of Letters Patent .nate' corresponding Patented Nov. 23. 1920. 1918. Serial No. 23mm.

ferred embodiment of the invention, and wherein similar l'ofel'ence'characters desigparts throughout the several news: Fi are l is an elevation spar plug,

Fig. 2 1s a vertical sectional view more particularly showingthe details ofconstruction of the plug,

Fi 3 is a transverse sectional view taken on the line 3-43 of Fig. 2 and looking in the direction of the arrows,

Fig. 4 is a plan view showing the closure plug for the shell of the device removed, and

Fig. 5 is a fragmentary sectional view showin the firing shell of the present improved strnctnre used in connection with a conventional type ofsparlc plug.

lncarrying out the invention I employ a hollow cylindrical elongated firing shell 10 providcg at its lower end with a substantially conical reduced nose or nozzle 11 in the apex of which is formed a restricted passage 12. The shell is externally threaded to detachably engage within the eonvenpf my improved *tional spark plug opening of an internal 'end of the shell is an enlarged wrench reeeiving portion [3 so that the shell ma be readily connected with or removed from such cylinder. 'lhreaded into the upper end of the shell axially thereof, is a closure plug 14 for the shell provided at its upper end with a radial flange 15. This flange is, as particularly shown in Figs. 1 and 3 of the drawings provided at its periphery with flat faces so that a wrench may be applied to the said flange for screwing the plug into position and interposed between the. said flange and the upper endof the shell is a suitahle gasket 16. This gasket is preferably formed' with an asbestos core inclosed within a copper jacket and is ada ted to provide a sealed joint between the p ug and the shell. Formed in the upper end of the plug 14 is, as particularly shown in Fig. 4, an annular recess or seat 17 and snugly fittingat its lower end within this seat is a porcelain 18. F or the purposes of the present invention this term porcelain shall be held to include a body of any suitable insulating material similar to'the porcelain 18.

seat 1? is a protecting band or collar 19 and formed through the porcelain axially thereof is an opening 20 tapering from the lower or inner end of the porcelain toward its upper end.

Formed through the plug '14, eceentrically thereof, is an opening 21 tapering from the lower end of the plug toward its upper end. This opening is inclined with respect to the axis of the pin and fitted through said opening is a mam electrode 22. This elec trode is formed with a longitudinally ta pered cylindrical bodfi' 23 having its small end presented upwar and surrounded by a similarly tapered 246i suitable msulatin material. his 'acket is preferably forme of mica and is a apted to snugly fit within the opening 21 of the plug to electrically insulate the main electrode with respect thereto. Fixed in the lower end of the body 23 of the said electrode axially thereof 'is a sparking terminal 24 projectin lon i- 25- tudinally from the said body and t rea ed upon the upper end of the e ectrode to confront the upper end of the porcelain 18 is.

a clamping nut 25. This nut, upon its lower side, is formed' with a concentric annular recess 26 and surrounding the main electrode within this recess is a spring locking washer 27 hearing between t e nut and a washer 28 interposed therebeneath. Thus, the nut 25 ma be adjusted'upon themain electrode for rawing the said electrodeup through the plug .4 to bind within the opening 21 thereof and accordingly rigidly connect the porcelain 18 with the plug. The plug 14, therefore, provides the body of my improved device while the nut 25 provides a single element connecting the main electrode and the porcelain with the said body. llpon the adjustment of the nut 25 the washer 27 will, of course, couct therewith for holding the said nut at adjustment and preventing accidental displacement or loosening of the nut while, at the'same time, the said washer will be protected and housed within the nut. Threaded upon the upper end of the main electrode is a thumb nut 29 adjustable for clamping a circuit wire therebeneath to connect the said wire with the electrodeand depending fromrthe plug 14 at the inner end of the said electrode, is a ground electrode 30 provided with a laterally directedsparking terminal 31 confronting the sparking terminal 24 of the said main electrode.

Thus. upon the energization of the. plug,

current will flow through the main electrode to the sparking terminal 24 to then jump to the sparking terminal 31 for creating a spark within the shell 10 when the current 1 i the sparking terminals 24 and 31 of the' plug will be housed within the shell 10, so ,that when the plug is connected with an enine cylinder and this shell projects into the iiring chamber of the said cylinder, the said shell will protect t e said sparking, termimile from the COOUllg influences of fuel mixture flowing into the said chamber, The dependability of the plug will, thegefore, be enhanced accordingly. Furtherm' re, it will be seen that the hollow shell 1 will provide a tiring chamber aboutthe said sparlfin terminals. Upon the-introduction of the uel lzharge into the engine cylinder, 9. portion of such charge will, of course, enter through the passugelZ into the chamber to be trapped therein. This trapping of'a portion of the charge within the shell will, as will be readily understood, result in such-trapped portion of the charge becoming heated from the wall of the shell and forming a primer charge within the firing chamber of the shell. flhercfore. when the plug js energized, ignition of the primer charge will readily occur and the dependability of the plug thus further enhanc ed. In this'connection. it is to be noted that the sparking terminals 24 and 31 are located within the firing shell to give oil a spark and cause initial ignition of the primer charge within the mass thereof so that the primer charge will begxpclled from the shell through the reduced passage 12 of the firing chamber thereof as a jet of flame into the charge of fuel mixture in the engine cylinder. Positive ignition of the fuel charge within'the cylinder will thus be rendered practicall certain. Owing to the provision of the re uced nose or nozzle 11 of the shell the i ited primer charge within the firin cham r will, as it flows through the said nozzle, be attenuated thereby to issue from the nozzle with unusual force in a jet of flame. This jetof flame will, therefore, tend to pierce the mass of the fuel charge in the engine cylinder to provide a thoroughignition thereof. This forcible ejection of the jet of flame from the shell will, furthermore, tend to maintain the passage 12 free ofany soot or carbon while, owing to the restricted nature of the said passage, fouling of the sparking'terminals by lubri cant within the engine cylinder will be re duced to a minimum. It is also to be noted that the compression within the engine cylinder will tend to more firmly wedge the main electrode in the opening 21 of the plug 14 and thus maintain a scaled joint between the said electrode and the lug so that leakage through the plug will a prevented.

It will. therefore, be seen that I provide a particularly efl'ective construction for the purpose'set forth. At the same ime the plug is characterized by sim licity of construction, it noted in nm gasbi that the shell 10 may be readily detached from the plug 14 or body of the device so that access may be easily had to the sparking-terminals while, should it be so desired the main electrode may be readily detached from the said plug or body and the porcelain dis )lacedr In Fig. 5 of the drawings I have illustrated a slight modification of the invention nary plug body, so that the conventional plug t USTlOSCl'llJell may be readily threaded into the upper end of the shell for connecting the pug therewith. The terminals 35 and 36 will then be dis )osed to ivc oil a spark within the firing chamber the shell, it being understood. of course, that the shell shall be threaded into an engine c 'linder, as described in connection with tie preferred construction. My improved tiring shell may, therefore, be readily employed in connection with the usual spark plug. In this connection it is to be noted that the opening in the u iper end of the shell is enlarged within t le wrench receiving )ortion 13 the eof to overhang the wall 0 the shell below the'said wrench receiving portion so that the diameter of the said opening corresponds to the major diameter of the shell. 't'onsequently', since the'.threads of the said opening are formed to coact with the threads upon the lower end of the body of an ordinary spark plug, plugs of various clillerent types may, without the necessity for any structural change therein, be readily engaged with the shell while, at the same time, the shell by being threaded to engage within the or inary spark .plug opening of an engine cylinder, may be readily used in connection with various different types of engines without the necessity for any modification in the plug openings of the cylinders' thereof.

Having thus described the invention, what is claimed as new is:

I claim:

A spark plug including a shell externally threaded for engagement in the spark plu orilicc of an engine cylinder and provided with an elongated frusto conoidal lower end portion having a minute opening at its apex, the inner face of the wall of the shell being smooth and of unbroken continuity, there being an internally threaded wrench receiving portion formed on the shell at its upper end, a plug threaded into the wrench re. ceiving portion of the shell and provided with an opening' therethrough located eccentrically with respect to the axis of the shell, a porcelain rested upon said plug, .a main electrode extending through the plug and porcelain and having a' tapered body, a tapered insulating packing fitting around the body of said electrode and coacting with the wall of the opening of the plug, a spark ing terminal projecting from the lower end of the body of the main electrode, and a ground electrode depending from the plug and provided with a sparking terminal to enact with said first mentioned terminal.

in testimony whereof I allix my signature. 

